Hypocalcemia in Cancer Patients: a Study Based on Ionized Calcium

The aim of this work was to study the prevalence of hypocalcemia in cancer patients based on ionized calcium and, as a secondary aim, the influence that hypocalcemia may have on survival. For this retrospective study, a representative sample of all the records of low and normal ionized calcium measured in 2014 was studied. Patients under 18 years and patients from the bone marrow transplantation service were excluded. The number of patients included in this study was 471. The median patient age was 63 years (18 to 91), and 247 (52%) were female. The most represented cancers were thyroid, colorectal, and breast. Ionized calcium was in the normal range in 331 (70%) patients and low in 140 (30%). In a univariable analysis, there were no significant differences in survival at 4 years between normal (47%) and low-level (42%) ionized calcium (p = 0.192), but there were differences in gender, age, the primary site, the number of metastatic sites, and the level of albumin. In the multivariable analysis, only the primary cancer, the number of metastatic sites, and the albumin levels were associated with survival. In a multivariable analysis excluding thyroid cancer, hypocalcemia remained not associated with survival. Hypocalcemia occurs in a variety of cancer types, and it does not have an influence on survival.